Routes in New York City, NY
Alan Vlakancic
December 7, 2025
This project uses stplanr and OSRM transport modeling package to compare optimal and euclidean transport paths for bus routes in New York City. Stplanr is a transport planning visualization R package that can be used to plan transit networks, in addition to transit planning elements such as identifying transit catchment areas, buffers, origin/destination data and ride frequency visualizations, among others. In their white paper, the devlopers of stplanr call for an accountable, transparent and democratized transit planning system that doesn’t rely on proprietary and often vastly different data sources and data processing softwares. As a result, they created stplanr so that regular data analysts can analyze data rather than relying on a more mysterious algorithm.
Although the package can visualize a whole host of data, this project will focus on comparing direct desire lines or “Euclidean” routes (as the crow flies), existing bus networks and stplanr’s optimized routes. Essentially: this can map the efficiency of the bus routes compared to the most direct route possible if there were no built environment factors in the way.
To adequately compare desire lines, and bus routes using the most efficient routes with the current street network, this project will require the below data sources. Each of these will be sourced and overlaid onto each other:
The overlay of these elements using leaflet will provide an interactive map that compares desire lines, existing bus routes, and optimized routes. The stplanr package will be used to calculate the optimized routes based on the bus shelter locations and the OpenStreetMap data. The comparison will be visualized using different colors and line styles for each type of route. This will be randomized with a 50 origin-destination pairs to make the computation manageable.
#install libraries
library(ggplot2) #for plotting graphs
library(dplyr) #data manipulation
library(stplanr) #od2line calculation, origin-destination programming
library(osmdata) #open street maps data
library(sf) #spatial data
library(tidyverse) #data manipulation
library(leaflet) #interactive map
library(purrr) #for map2 function
library(kableExtra) #for attractive table formatting
library(scales) #for comma function
library(plotly) #for interactive plots#SHAPEFILES AND MAP
#This first step creates the basemap and brings in the data for processing in later chunks
bbox <- c(left = -73.96, bottom = 40.54, right = -73.70, top = 40.81)
#create bounding box for NYC
nyc_map <- "data/"#
#nyc basemap, downloaded from nyc open data. source: https://search.r-project.org/CRAN/refmans/ptools/html/nyc_bor.html
nyc_sf <- st_read(nyc_map, quiet =TRUE)
#bring in nyc_map as a sf
shelters_sf <- read_csv("data/Bus_Stop_Shelter_20251020.csv")
#this brings in the bus stop shelter information. source: https://data.cityofnewyork.us/Transportation/Bus-Stop-Shelters/qafz-7myz
shelters_sf_fix <- st_as_sf(shelters_sf, coords = c("Longitude","Latitude"), crs = 4326)
#convert to sf object with the correct coordinate reference system
osmdata::set_overpass_url("https://overpass-api.de/api/interpreter")
#set overpass url for open street maps, finds specific data package, the below query will use this
osm_data <- opq(bbox = bbox) %>%
add_osm_feature(key = "highway", value = c("primary","secondary")) %>%
osmdata_sf()
#import data for primary and secondary highways from open street maps
#opq is overpass query, which is basically where you want to look# STPLANR FUNCTIONS
#this step combines both stplanr and sf functions to create desire lines and optimized routes between O-D pairs
shelters_sf_fix <- shelters_sf_fix %>%
mutate(id = paste0("S", row_number()))
#add ID column for origin-destination pairs so they have a corresponding number
flow_all <- expand.grid(o = shelters_sf_fix$id, #create origin
d = shelters_sf_fix$id, #create destination
stringsAsFactors = FALSE) %>% #make sure they aren't factors
filter(o != d) %>% # this remove self-pairs so O is not D
mutate(trips = 1) %>% #add trip count of 1 for each pair
sample_n(50) #sample 50 random paris to avoid blowing up the computer
desire_lines_all <- od2line(flow_all, zones = shelters_sf_fix, zone_code = "id") #use od2line function to create desire lines (euclidean) for all pairs
shelter_coords <- shelters_sf_fix %>%
st_coordinates() %>%
as.data.frame() %>%
bind_cols(id = shelters_sf_fix$id)
#extract coordinates and bind with ID column
route_single <- function(o_id, d_id) { #function to create a single route between origin and destination
o <- shelter_coords %>% filter(id == o_id)
#filter to get origin coordinates
d <- shelter_coords %>% filter(id == d_id)
#filter to get destination coordinates
r <- try(route_osrm(from = c(o$X, o$Y),
to = c(d$X, d$Y)), silent = TRUE)
#use try to catch errors (e.g., no route found)
if (inherits(r, "try-error")) return(NULL)
#if route found, return the route
return(r)
}
routes_list <- purrr::map2(flow_all$o, flow_all$d, route_single)
#create routes for all origin-destination pairs using the route_single function by routing in paralell
routes_list <- routes_list[!sapply(routes_list, is.null)]
#remove any NULL results (failed routes)
routes_sf <- do.call(rbind, routes_list)
#combine all routes into a single sf object#ROUTE & DESIRE LENGTH CALCULATION, MEAN & PCT CHANGE
#these calculations are for printing as a cleaned up presentable table through kable, and comparing means and providing data to be displayed in a popup on the leaflet map
routes_projection <- st_transform(routes_sf, 32618)
desire_projection <- st_transform(desire_lines_all, 32618)
#ensures the correct, projected shapefile for computation not mapping
route_length <- st_length(routes_projection)
desire_length <- st_length(desire_projection)
#compute lengths
route_length <- as.numeric(route_length)
desire_length <- as.numeric(desire_length)
#convert lengths to numeric values
lengths_tbl <- tibble(
route_m = route_length,
desire_m = desire_length,
origin = flow_all$o,
destination = flow_all$d
)
#create tibble to compare lengths in the final map w/ IDs
lengths_tbl_print <- tibble(
route_km = route_length / 1000,
desire_km = desire_length / 1000,
origin = flow_all$o,
destination = flow_all$d
) %>%
mutate(
ID = row_number(),
difference = round(route_km - desire_km)
) %>%
mutate(
route_km = comma(round(route_km)),
desire_km = comma(round(desire_km))
) %>%
arrange(desc(difference))
#tidy data for later printing in a kable
lengths_tbl_print <- lengths_tbl_print %>%
select(ID, origin, destination, route_km, desire_km, difference)
mean_route <- mean(route_length, na.rm = TRUE)
mean_desire <- mean(desire_length, na.rm = TRUE)
#calculate means for both route and desire lengths
percent_change <- ((mean_route - mean_desire) / mean_desire) * 100
#calculate percent change
mean_lengths <- data.frame(
type = c("Route Length", "Desire Line Length"),
mean_length_m = c(round(mean_route), round(mean_desire)))
#put these into a data frame, rounded to whole numbers
mean_lengths <- mean_lengths %>%
mutate(
mean_length_km = mean_length_m / 1000,
percent_change = c(percent_change, NA)
)
#add km conversion and percent change to the data frame, i converted to KM for ease of computation (ie: dividing by 1,000)
mean_lengths_print <- mean_lengths %>%
mutate(
mean_length_km = comma(round(mean_length_m / 1000)),
percent_change = comma(round(percent_change))
)
#tidy data for later printing in a kable#LEAFLET PREP
#this step makes sure all the coordinate systems are correct and creates popup data and color palette for the leaflet map
nyc_leaflet <- st_transform(nyc_sf, 4326)
roads_leaflet <- st_transform(osm_data$osm_lines, 4326)
desire_leaflet <- st_transform(desire_lines_all, 4326)
routes_leaflet <- st_transform(routes_sf, 4326)
#transform all data to WGS84 for leaflet mapping
desire_leaflet_popup <- paste0(
"<b>Desire Line</b><br/>",
"Origin: ", desire_leaflet$o, "<br/>",
"Destination: ", desire_leaflet$d, "<br/>",
"Desire Line Distance: ", round(lengths_tbl$desire_m / 1000), " km"
)
#create popup info for desire lines for interactive map
routes_leaflet_popup <- paste0(
"<b> Route</b><br/>",
"Origin: ", desire_leaflet$o, "<br/>",
"Destination: ", desire_leaflet$d, "<br/>",
"Route Distance: ", round(lengths_tbl$route_m / 1000), " km<br/>"
)
#create popup info for routes for interactive map
pal_desire <- colorNumeric(
palette = "viridis",
domain = lengths_tbl$desire_m
)
#create color palette for desire lines based on distance
pal_routes <- colorNumeric(
palette = "inferno",
domain = lengths_tbl$route_m
)
#create color palette for routes based on distance
selected_ids <- unique(c(flow_all$o, flow_all$d))
#get unique IDs of sampled shelters
selected_shelters <- shelters_sf_fix %>%
filter(id %in% selected_ids)
#filter shelters to only those that were sampled#LEAFLET MAP
#this step creates the interactive leaflet map with all the data layers
leaflet() %>%
addProviderTiles("CartoDB.Positron") %>%
addPolygons(data = nyc_leaflet,
color = "black", weight = 3,
fillOpacity = 0.1,
group = "NYC Boundary") %>%
# add background w/ cartodb tiles
addPolylines(
data = desire_leaflet,
color = pal_desire(lengths_tbl$desire_m),
weight = 3,
opacity = 0.7,
popup = desire_leaflet_popup,
group = "Desire Lines"
) %>%
addPolylines(
data = routes_leaflet,
color = pal_routes(lengths_tbl$route_m),
weight = 3,
opacity = 0.8,
popup = routes_leaflet_popup,
group = "Routes"
) %>%
addLegend(
pal = pal_desire,
values = lengths_tbl$desire_m,
title = "Desire Line Distance (m)",
position = "bottomright",
group = "Desire Lines"
) %>%
#add a legend for desire lines
addLegend(
pal = pal_routes,
values = lengths_tbl$route_m,
title = "Route Distance (m)",
position = "bottomleft",
group = "Routes"
) %>%
#add a legend for routes
addCircleMarkers(data = shelters_sf_fix,
color = "blue",
radius = 1,
popup = ~id,
group = "Bus Shelters") %>%
#add all bus shelters
addCircleMarkers(
data = selected_shelters,
color = "purple",
radius = 6,
fillOpacity = 0.9,
group = "Sampled Shelters"
) %>%
#add sampled bus shelters with purple markers
addLayersControl(
overlayGroups = c("NYC Boundary", "Sampled Shelters",
"Desire Lines", "Routes",
"Bus Shelters"),
options = layersControlOptions(collapsed = FALSE)
)| Type | Mean Length (m) | Mean Length (km) | Percent Change (%) |
|---|---|---|---|
| Route Length | 17161 | 17 | 20 |
| Desire Line Length | 14323 | 14 | NA |
# Lengths Comparison Table
lengths_tbl_print %>%
select(-ID) %>%
kable(col.names = c("Origin", "Destination", "Route Length (km)", "Desire Line Length (km)", "Difference (km)"),
caption = "Comparison of Route Lengths and Desire Line Lengths, By Difference") %>%
kable_styling(full_width = FALSE, position = "center")| Origin | Destination | Route Length (km) | Desire Line Length (km) | Difference (km) |
|---|---|---|---|---|
| S1016 | S2489 | 30 | 16 | 14 |
| S2966 | S3347 | 45 | 34 | 10 |
| S991 | S2380 | 30 | 21 | 9 |
| S3307 | S3010 | 45 | 36 | 9 |
| S457 | S3327 | 22 | 14 | 8 |
| S2579 | S449 | 26 | 20 | 6 |
| S3157 | S2030 | 27 | 22 | 5 |
| S2894 | S1256 | 27 | 22 | 5 |
| S1198 | S2223 | 19 | 14 | 5 |
| S1399 | S2947 | 15 | 11 | 4 |
| S3181 | S905 | 18 | 14 | 4 |
| S3080 | S1006 | 19 | 15 | 4 |
| S3325 | S1905 | 34 | 30 | 4 |
| S3121 | S604 | 24 | 21 | 3 |
| S649 | S3068 | 20 | 17 | 3 |
| S282 | S2145 | 14 | 11 | 3 |
| S3275 | S1106 | 45 | 42 | 3 |
| S803 | S2860 | 19 | 17 | 2 |
| S1086 | S2135 | 14 | 12 | 2 |
| S2558 | S2943 | 13 | 11 | 2 |
| S296 | S1933 | 17 | 14 | 2 |
| S601 | S118 | 11 | 9 | 2 |
| S1795 | S273 | 12 | 10 | 2 |
| S407 | S2848 | 19 | 17 | 2 |
| S40 | S2514 | 17 | 15 | 2 |
| S3098 | S1665 | 17 | 15 | 2 |
| S2283 | S189 | 16 | 14 | 2 |
| S2049 | S3229 | 29 | 27 | 2 |
| S2007 | S1249 | 15 | 14 | 1 |
| S555 | S1666 | 9 | 8 | 1 |
| S1664 | S2448 | 11 | 10 | 1 |
| S491 | S2884 | 14 | 13 | 1 |
| S558 | S215 | 9 | 8 | 1 |
| S1733 | S2074 | 12 | 11 | 1 |
| S665 | S2583 | 19 | 18 | 1 |
| S488 | S310 | 10 | 9 | 1 |
| S782 | S1831 | 11 | 10 | 1 |
| S1247 | S2904 | 8 | 6 | 1 |
| S40 | S1612 | 12 | 11 | 1 |
| S607 | S2938 | 10 | 9 | 1 |
| S922 | S1434 | 5 | 5 | 1 |
| S2841 | S2417 | 12 | 10 | 1 |
| S1590 | S2731 | 7 | 6 | 1 |
| S435 | S1984 | 19 | 18 | 1 |
| S3133 | S53 | 6 | 5 | 1 |
| S1676 | S2087 | 6 | 5 | 1 |
| S2887 | S2329 | 2 | 1 | 0 |
| S855 | S2197 | 14 | 14 | 0 |
| S255 | S37 | 2 | 2 | 0 |
| S885 | S229 | 2 | 2 | 0 |
# Bar Plot of Differences via plotly
gg1 <- ggplot(lengths_tbl_print, aes(x = ID, y = difference, text = paste("Origin: ", origin, "<br>Destination: ", destination))) +
geom_bar(stat = "identity") +
scale_fill_viridis_b()+
labs(
title = "Difference Between Route Length and Desire Line Length",
x = "Route ID",
y = "Difference (km)"
) +
theme_dark()
gg1_plotly <- ggplotly(gg1)
gg1_plotlyThe mean route length for the optimized routes for this particular sample run is 17.16 km, while the mean Euclidean desire line length is 14.32 km. This represents a percent change of 19.81% longer for the optimized routes compared to the direct desire lines. The interactive map above visualizes these routes, with desire lines colored based on their lengths and Open Street Routing Machine (OSRM) routes similarly colored with a different theme.
The results indicate that the optimized OSRM routes are significantly longer than the direct desire lines, which is generally expected given the constraints of the built environment and road network. The percent change of 19.81% suggests that while the desire lines represent the most direct path between two points, real-world travel must navigate around obstacles, follow roadways, and adhere to traffic regulations etc.
There were many obstacles when creating this project. Firstly, the stplanr has a number of vestigial functions that are served by “sf” package, such as “st_as_sf”, which made it difficult to find the right functions to use, often the code would break and I would have to go searching for the reason.
The OSRM routing service can also be unreliable at times, particularly for points that are very close together or in areas with limited road connectivity. This led to some origin-destination pairs not being counted as a “route”, which had to be filtered out of the final analysis. At first, these routes did not intersect with the correct Bus Shelters (ie: the routes were truly random, instead of 50 pairs, there were essentially 100).
As a result, the purrr package was used to map over the origin-destination pairs to create overlapping routes, which was a complex package to comprehend at first. Only the map2 function, which essentially applies a function to two lists in parallel, was used in this project.
Other functions such as “scales” (for “comma” & “round” functions tidying up data for presentation in a table), didn’t work properly at first, as they change the numeric to a character. Plotly and kablextra were straightforward enough.
Methods: Future research could expand the sample size to include more origin-destination pairs, or even all bus stops. Incorporating real-world travel time data, traffic patterns, and transit schedules could provide a more comprehensive understanding of route efficiency. Further analysis could also explore the impact of different modes of transportation, such as cycling or walking, on route optimization and efficiency.
Representation: A number of visual elements could be changed, such as mapping the two routes together, so that when you select one, the other one is highlighted. Different color schemes could be used for more differentiation of routes and desire lines. A buffer could be added to the polylines to make it easier for the user to select the polylines to see the popup information. Right now, you need to click directly on it which is difficult.